Technologies based upon semiconductor materials and devices have a remarkable track record of commercial achievement. Silicon-based solid state electronics have given us computing technology that has doubled in performance every two years (Moore's Law) for over forty years. Additionally, compound semiconductor optoelectronics, mostly Gallium Arsenide (GaAs) and Indium Phosphide (InP) based III-V semiconductor laser diodes, have given us communications technology that doubles the data coming out of an optical fiber every nine months (Butter's Law of Photonics). Semiconductor technology is now being applied to energy and energy efficiency. Solar cell devices based on Silicon and other semiconductor materials have recently experienced significant commercial success. However, it is widely recognized that there is little room left for significant improvement in solar cell power production efficiencies. In other words, there appears to be no equivalent opportunity for a Moore's Law type of improvement with solar cells. By contrast, thermoelectric materials for power generation from heat sources are increasingly being recognized as having the potential for a Moore's Law type of sustained performance improvement in the clean technology area. Thermoelectric materials can be used to form thermoelectric generators and thermoelectric coolers.
The figure-of-merit (ZT) of a thermoelectric material is a dimensionless unit that is used to compare the efficiencies of various thermoelectric materials. The figure-of-merit (ZT) is determined by three physical parameters: the thermopower α (also known as a Seebeck coefficient), electrical conductivity σ, and thermal conductivity k=ke+kph, where the ke and kph are thermal conductivities of electrons and phonons, respectively; and absolute temperature T:
  ZT  =                              α          2                ⁢        σ                    (                              k            e                    +                      k                          p              ⁢                                                          ⁢              h                                      )              ⁢          T      .      Increasing this value to 2.0 or higher will disrupt existing technologies and will ultimately enable more widespread use of thermoelectric systems. From the equation above, it can be seen that the figure-of-merit (ZT) is inversely proportional to the thermal conductivity of the thermoelectric material. As such, lowering the thermal conductivity of a thermoelectric material will increase the figure-of-merit (ZT). Thus, there is a need for a low thermal conductivity thermoelectric material.